Total knee replacement is presently an accepted medical treatment for arthritic knee pain that has failed or been unresponsive to conservative management. Over the past few decades, the surgical technique has continuously evolved. Recently, new minimally invasive surgery (MIS) techniques have demonstrated benefits to the surgical patient with faster rehabilitation and potential for less morbidity. These new techniques require new instruments because of the limited exposure of the anatomy.
Traditional total knee replacement surgery requires a wide exposure with an incision of 8-10 inches. The joint surfaces of the femur and the tibia, and frequently the patella, are replaced with metal and polyethylene components. In this approach, a lengthy extensile exposure is achieved by a long incision that extends through the quadriceps muscle and the patella is completely inverted 180 degrees so that the undersurface of the patella is directly facing the surgeon. Frequently, the patella demonstrates significant arthritic wear and requires replacement. The patella is a very irregular bone, and with arthritis the wear creates further unevenness. Various patella resection guides (jigs) have been designed to assist the surgeon in the removal of the patella undersurface. The resection guides allow the surgeon an opportunity to review the planned resection. The guide is carefully placed into position and firmly clamped into position.
Surgeons sometimes use a freehand technique which may leave the cut surface with significant irregularities that would be potentially detrimental to the final resurfacing. It is very necessary that the patella resection guide not become dislodged during the process of patella resection because an irregular surface may result Minimally invasive surgery (MIS) now appears to be the next step in the evolution of total knee arthroplasty. This technique utilizes a 10-12 cm (4-5 inch) incision along the medial border of the patella. A small incision of 2-3 centimeters is used to release the medial muscle, the vastus medialis obliques, one of the four muscles that are part of the quadriceps musculature that control the patella. The patella is next inverted only 90 degrees and is evaluated by the surgeon on end, with the lateral patella placed on the femur. Current patella resection guides are bulky and are difficult to grasp the patella in this 90 degree position.
There are always new breakthroughs in medicine. MIS is now here and is being further refined by the many innovative orthopedic surgeons around the world. Furthermore, to assist in the limited exposure allowed with the MIS approach, computer navigation of the knee has greatly provided the surgeon important information for neutral alignment of the total knee components for the potential of a longer lasting result. New techniques will require new instruments. The inventive patella resection guide and method of applying said patella resection guide in a surgical procedure as described herein is one of the instruments that will be necessary as knee surgery continues to evolve.